CVE-2026-115349
Published:October 22, 2026
Updated:October 23, 2026
Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in src/mistune/helpers.py. Attackers can submit markdown with deeply nested square brackets triggering quadratic parsing time, exhausting server CPU with small crafted requests.
Affected Packages
mistune (CONDA):
Affected version(s) >=3.0.0 <3.3.1Fix Suggestion:
Update to version 3.3.1https://github.com/lepture/mistune.git (GITHUB):
Affected version(s) >=v3.0.0a1 <v3.3.0Fix Suggestion:
Update to version v3.3.0mistune (PYTHON):
Affected version(s) >=3.0.0a1 <3.3.0Fix Suggestion:
Update to version 3.3.0Related Resources (2)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Inefficient Regular Expression Complexity